1. Field of the Invention
The present invention relates to a radio-frequency identification (RFID) communication scheme, and more particularly to a near field communication (NFC) apparatus using the RFID technology, and a method thereof.
2. Description of the Prior Art
The latest mobile phones with a near field communication (NFC) function have built-in radio-frequency identification (RFID) circuits. The RFID circuit includes the capabilities of peer-to-peer communication with an external RFID circuit, reading data of an external RFID tag, and simulating as an RFID tag. A user can therefore replace an original RFID card (such as a travel card) with his/her mobile phone when utilizing an underground travel system, such as the Taipei's Mass Rapid Transit (MRT) system. A denouncing problem can arise, however. For instance, when the user enters a station A of the MRT system, the user uses the RFID circuit within the mobile phone to communicate with an RFID reader of a gate in the station A for recording the station the user enters. When leaving the MRT system at another station B, the user uses the RFID circuit to communicate with an RFID reader of a gate in the station B, and then the RFID reader of the station B reads the recorded information from the RFID circuit for determining the traveling expenses the user should pay. If the battery of the mobile phone is exhausted while the user is still inside the MRT system, the user cannot use the RFID circuit built within the mobile phone to communicate with the RFID reader at an exit gate; this is because the RFID reader is designed as being powered by the battery of the mobile phone. In this situation, the user cannot pay the traveling expenses for the MRT system using the mobile phone. It is not convenient for the user. Additionally, when the user changes his/her mobile phone, the user is faced with the risk of losing any remaining money recorded by the old mobile phone since the amount may not be transferred to the user's new mobile phone. Regularly, the amount of money is recorded on another circuit within the mobile phone. Thus, unless a conversion scheme between different mobile phone manufacturers or different service providers can be designed beforehand, the money cannot be directly transferred to and recorded in a circuit built within the new mobile phone when the user changes his/her mobile phone.
Regarding a well-known conversion scheme, the RFID circuit is arranged to transmit data associated with the amount of remaining money to the host circuit of the old mobile phone, and the host circuit is arranged to record the data into the SIM card. Thus, after changing mobile phones, if the SIM card is still used by the user, the user can continue to use the remaining money as payment. Moreover, in the situation where the battery of the mobile phone is exhausted while the user is inside the MRT system, a recently provided solution proposes that the SIM card includes a dual interface. That is, the SIM card has the communication functions of both a SIM card and RFID. The SIM card is connected to an antenna of another NFC circuit and installed within the mobile phone before it is used. Therefore, the user can still use the mobile phone to replace the conventional RFID card to pay traveling expenses when the user travels by the MRT system. When the user exits the MRT system, an RFID reader installed at the gate communicates with the above-mentioned SIM card for the purpose of collecting traveling expenses. The SIM card having the dual interface, however, only provides the function of making payments, but does not include the functions regarding pier-to-pier data transmission and reading data of an RFID tag. It is hoped that a single handheld product such as a mobile phone can integrate diversified applications, where the above-mentioned RFID circuit built in the mobile phone will be required. If the RFID circuit, the SIM card having the dual interface, and the related antenna connected to the SIM card are all installed within the mobile phone to achieve the objective of the mobile phone being integrated with diversified applications, then, in practice, the mobile phone should include two antennas operating at the same frequency. This substantially increases the manufacturing costs, the size of the circuit area of the mobile phone, and the layout difficulty.